There have been numerous attempts in the prior art to provide a means for effectively and easily brushing and curling hair with a heated brush. Typical of the prior art attempts to provide suitable brush means are U.S. Pat. Nos. 675,527; 1,258,375; 1,393,635, 1,436,957; 4,030,158; 4,314,137; and 4,368,376.
These devices fall into two classes: first, brushes used solely for brushing hair typified by U.S. Pat. Nos. 675,527; 1,258,375; 1,393,635; 1,436,957; and 4,030,158 which are used primarily for brushing hair in straight strokes and to provide body and to assist in drying of hair when used with drying devices commonly known as blow dryers; and second, heated curling irons or brushes used to style the hair and impart a wave thereto typified by U.S. Pat. Nos. 4,314,137 and 4,368,376.
Although brushes in the former group are generally satisfactory for conventional brushing, they are unsuitable for curling or waving hair. As to the latter group, it has been found that while generally they perform the function for which intended, i.e., to curl or wave the hair, there is a tendency for the hair to tangle in the curling brush or to be snarled by use of the brush. Furthermore, brushes of either type, can, depending on their construction irritate or scratch the scalp when used because of the use of generally pin-shaped bristles.
In addition, where metal bristles are employed, user contact with the heated bristles can result in painful contact, particularly when the user grips the ends of the hair to keep the ends from slipping off the curler brush when rotation of the hair on the curler is started.
Another problem that arises with the use of prior art brushes is that tangling occurs from twisting the brush while winding the tresses. Bristle curling brushes designed according to prior art techniques frequently cause tangling after several rotations of hair around the brush, as the pins or bristles become caught in the underlying hair. Such brushes generally are constructed of metal pins or plastic teeth mounted in a support structure which terminates in a handle. Tangling of the hair can occur in brushes having either metal pins or plastic teeth. However, the plastic teeth of some prior art brushes do not permit more than one layer of hair to get below the tips of the teeth and in such brushes, the tangling problem is less severe. In brushes having metal bristles, on the other hand, the shape, flexure and friction coefficient of the pins does permit layers of hair to slide down the pins and it has been found that severe tangling of the hair results.
In addition to the aforementioned prior art devices employed to brush or curl the hair, there is yet another category of devices commonly employed in hair curling. These are generally referred to as hair curlers or winders and are externally heated, cylindrical devices around which several layers of hair are wrapped after the device has been preheated to aid in curling. Typical of these devices are U.S. Pat. Nos. 3,566,887 and 3,706,315. Although these devices are suitable for hair curling, they are unsuitable for use in brushing hair. Furthermore, because of their design, they are restricted as to the number of layers of hair, generally one or two, which can be wound through the tabs or spades of the winder.
The size and spacing of the heated bristles should preferably be such as to prevent the users' fingers from being able to touch the barrel. Users generally do not intentionally touch the barrel. Instead, they place their fingers on top of the hair ends when starting rotation of the rush to keep the ends from slipping off. In placing their fingers in such a manner, the users make contact with the bristles. With plastic bristles this is not as much of a problem since they are cooler and do not conduct heat as readily. However, with devices having bristles of heat-conductive composition, painful contact with the bristles adjacent to the heated housing can occur. This problem is substantially reduced by the instant invention which minimizes the need for the user to have to grip the ends of the hair in order to start rotation of the brush. The gripping of the hair ends during start of rotation may be accomplished by providing a barrel surface having dimples, a roughened surface, a flocked surface or a rubber surface.
The tips of the bristles used in the heated curling brushes of the present invention which are in contact with the scalp should be relatively smooth to avoid scalp irritation during use. The tips may be coated or rounded to provide the desired smooth surface. Coating the tips with a thin plastic thermal insulating material also enhances comfort and safety by slightly decreasing tip temperature.
There is no known prior art disclosing a bristle curling brush showing use of bristles which are relatively tangle-free and able to be heated to enable application of heat throughout the layers in a hair tress. Moreover, while heated bristle curling brushes are known such as that shown in U.S. Pat. No. 4,314,137, there is no suggestion in such prior art devices of how to efficiently heat loop or arch-shaped bristles. It has been found that the use of arch-shaped bristles, each end of which is in thermal contact with a heated core, enables the bristle tips to reach a satisfactory operating temperature with the use of a lower temperature heated core than is possible with straight, pin-shaped bristles. It will be understood that, while the term "arch-shaped" is generally used herein, the shape of the bristles may be other than an actual arch. The bristles may be star-shaped, substantially round or rectangular, solid or hollow, etc. The only requirement being that the base of each bristle subtend an arcuate length of more than about 20.degree. on the barrel.